what caused this young woman to join them? we went to the french neighborhood where which she lived searching for answers. >> reporter: these were the last words of hasna. earlier, police had said the 26-year-old had detonated an explosives vest as police closed in. but now, forensics teams determined that the bomb was actually triggered by either the alleged ring leader or the other so far unidentified suspect killed in the operation. investigators are now struggling to understand how a young woman described as modern and fun loving veered into the path of the deadly terrorist network. until weeks ago, she lived here with her family. police brought her mother and brother in for questioning on thursday. >> we're in the neighborhood where she was living. it's a rough neighborhood at the best of times.